Lagondaforum

Subject: Re: Water Pump Modification

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You can`t move the bolting face on the pump drive pulley,the
body of the punp is about 3mm from the inside of that face.
It isn`t advisable to remove the bypass system, this is there to
prevent hoses being blown off. The pump will produce upto 45psi when the engine is reved. Are you shore the temp
gauge is wright, test it by disconectind it and imerseing in a
kettle and boil it. It should register 100c,( granny sucking eggs).
Have the rad reversed flushed. Is there anyway to increase
air flow through the engine compartment.There are many things to consider,are the bleed holes for the liners weeping,
these engines tend to silt up around the liners. Years of rad
weld to seal up leeks tends to build up at the bottom of the
liners. Fit a 72c stat, check ignition and fueling. is there a alloy
cowl bolted to the rad encircleing the fan to duct all the air through the rad

Subject: Re: Water Pump Modification

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Thanks for advice Ray, very helpful.

David, did you once mentioned something about the seal which runs around the gutter in the engine bay? I was thinking that the original seal could be swapped for a low profile finisher instead, this would create quite a large gap for the warm air to escape out of...?

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Subject: Re: Water Pump Modification

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Hi Christian.
I can`t see the reasom for sealing the bonnet edges, this will increase the heat soak in the motor causing vapour lock in the carbs. Remember these machines where made at a time when the roads where less congested, speeds where higher keeping air flow up. Running these engines on unleaded fuel makes them run hotter. The point about the temp gauge is somthing I found some years ago on a Aston Martin DB3S, the kettle boild and the gauge read 75c, the owner swore blind he neverraced it above 85c, hence flash over heating of the pistons.

Subject: Re: Water Pump Modification

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Thanks Ray, I think the slats under the bonnet are meant to keep the air flowing even with the seal in place but unleaded fuel does add an extra element to be considered.

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Subject: Re: Water Pump Modification

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Andy Chapman would stress that the only proper way in for air is through the radiator aperture, so the slats are for air exit, aided by the low pressure areas in the front wheel arches. Air in through the unsealed bonnet allows turbulence or static under-bonnet air which as Ray says causes heat soak; from practical experience heat soak is reduced if the bonnet is "up" on its first catch where flow is aided by the low pressure region at the base of the front windscreen, which suggests that the bonnet seal might be usefully omitted in this area. That said there is a slight lip on the underside of the bonnet here which might disable the flow when the bonnet is fully closed. It's for these reasons that I'm sceptical about the effectiveness of the additional bonnet air inlet scoops fitted to the Australian car 110

Subject: Re: Water Pump Modification

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On the Lagonda circa 1960s I don`t know how mutch room is
available front or rear of rad, but any modern electric fan
needs ducting. The problem with fans placed in front spill a large amount of cooling air out to the side, usually returning
through the fan. To the rear of the rad the fan sucks the air
from the sides instead of through the rad. I would think the
arrangement on the Lagonda is as the DB4/5/6. If you are
retaining the engine driven fan, I would look at a ducted front
fan, remember they pull a large amount of amps and therefore
require large cable. Power it by rad switch placed in the top
hose area, and a relay may be 2 in parallel. Startup amps
can be between 25/30 depending on motor and fan.

Ray

Subject: Re: Water Pump Modification

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The setup I've gone with is a Revotec thermostat at the bottom outlet of the rad with a 16" 80A electric fan which pushes through around 2100CFM , this sits in front of the rad. The Revotec thermostat is an adjustable inline type rather than the capillary type (which I think looks crude).



The Rapide radiator is ducted on both sides, though on the engine side the cowl is designed to fit the mechanical fan. I have removed the mechanical fan as I don't think it will add benefit when needed and may further restrict air flow. In slow traffic on a hot day the mechanical fan is spinning slowly when you really need it to be fast. I've only tried the new fan a few times but it seems to work well letting the engine run up to around 93 and then bringing it back down to around 88...ish.



Also a mechanical fan reduces the HP by around 5%.

I'll let you know how I get on.

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Subject: Re: Water Pump Modification

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I hope you've got enough electrical power to cope with that fan load as well as other stuff, e.g. at night in rain!

Subject: Re: Water Pump Modification

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I've put in a very large battery so as long as the dynamo output keeps up then I should be fine...

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Subject: Re: Water Pump Modification

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I think you should be looking at fitting a modern large output
alternator to keep up with demand. Battery size is relevent
to starting demand, your dynamo only has an output
29/31 amps if your lucky remember it is Lucas. This is the
reasom they fitted a ballast resistor ignition systems, with
the battery in the boot there is a large drop in volts at the
coil on start up. Even the converted dynomo/alternator units have a hard time with demand.

Ray.